Manuel Alvarez Bravo.

MoMA/ROBERT MILLER/WITKIN GALLERY/THROCKMORTON FINE ART

In the great portrait Frida Kahlo in Manuel Alvarez Bravo's Studio, 1930s, the painter's head, with its penetrating, questioning eyes, is twice rhymed elsewhere: in the mirrored ball next to her arm, which (like the mirror in Velasquez' Las Meninas) gathers, concentrates, and somehow expands the space in the studio, thereby returning it as a distorted reflection; and in the carving on the floor behind her, staring blind-eyed and open-mouthed at nothing. This seems to say that, like any art, photography can encompass the function of the all-gathering yet alienating mirror, or the unseeing yet minatory messenger from beyond; but centrally, it can only be this questioning human intelligence, a gaze that neither wholly accepts nor rejects.

Photography is an art of rendering the surfaces of things, and in this photograph, as in so many by Alvarez Bravos the presence of surfaces is manifest to an astonishing level of detail, and with rare multiplicity. Kahlo's clothing alone, with its six different textures and patterns, is lent a symphonic richness. Surfaces, in such images, as they become particularized and multiply, define a space that is not that of realism. That space becomes more intricate than the one we inhabit, and surprisingly capacious. Things, people, even the attentive gaze itself, all tend to lose themselves in it, though not irretrievably. Space swallows things, but not whole (as in The Crouched Ones, 1934, or Return of the Fishermen, late 1940s). It's as though they haven't had time to become completely lost, because in these photographs time, no longer the congealed element of monuments, of statues, as it tended to be in photographs of the nineteenth century, is also not the fleetingly glimpsed velocity it would become later; things within the flow of time inspire neither the complacency in their endurance nor the frenzy of distraction. They bear watching. Not looking, not noticing, but watching.

Manuel Alvarez Bravo has maintained this tender, sly, and fascinated vigilance over his native Mexico for some seventy years now. He was never the peripatetic figure so many photographers have been. His ventures out of Mexico City have been to remote parts of his own country, as when he went to make a film about a matriarchal culture in Tehuantepec. For all that, it would be misleading to see his art as fundamentally nationalistic or folkloric. The images are typically oblique and allusive, far from the collective address of the muralists who so impressed him when, in the early '30s, he was commissioned to document their work. Even in calling for a popular art, Alvarez Bravo went on to define it as being "fugitive in character, of sensitive and personal quality."

Alvarez Bravo's MoMA retrospective, with some 170 images, along with three fairly substantial gallery shows, gives us almost more of him than we can easily take in. Yet it would be hard to say that there is anything one would happily leave out, other than a certain repetition of some of the best-known images from show to show. If anything, MoMA does Alvarez Bravo an injustice by devoting less space to his work from the '50s to the present than it does to his early work. The shows at Robert Miller and Witkin, in particular, help remedy that defect to some degree, revealing that the later work has become more severe and, like some of his earliest experiments in the late '20s and early '30s, nearly abstract. Works like La luna falsita (Little artificial moon, 1958), or Hoyo en la pared (Hole in the wall, 1974) with their floating forms, even recall another underrated body of late work, that of Joan Miro, but they also possess a poetic tension absent from other photographs influenced by abstract painting, such as those of Aaron Siskind.

Just as the "popular," in Alvarez Bravo's understanding, is inseparable from the personal, so the natural and the artificial are intertwined. In Growing Tree, 1930s, we see the complicated framework constructed to support the growth of a young tree, and we note how it looks almost as fragile as the plant it means to support. It's no surprise to find confirmation that the famous image The Good Reputation Sleeping, 1939, in which Alvarez Bravo came closest to the Surrealists who would have been happy to claim his adherence - a beautiful young woman dozes, her hips and ankles swathed in bandages, spiny cacti inexplicably scattered around her - was a set-up; yet its juxtapositions are no stranger than many others he's simply observed.

In 1931 Alvarez Bravo gave one of his images the title Optical Parable. He could have given the same name to any of them: they are concrete in their means yet oblique in their significance; though they seem to impart a lesson, its application is ambiguous. So as for the well-known younger photographer who told me, "I model my life on Man Ray but model my work on Alvarez Bravo," and then didn't want to be quoted: well, you know who you are; but to model one's life after Alvarez Bravo's work - the challenge posed by any parabolic art - would be a deeper project.

Barry Schwabsky is the author of The Widening Circle: Consequences of Modernism in Contemporary Art (Cambridge University Press, 1997).